x264 is a free software library and application for encoding video
streams into the H.264/MPEG-4 AVC format.

Encoder features:
 * 8x8 and 4x4 adaptive spatial transform
 * Adaptive B-frame placement
 * B-frames as references / arbitrary frame order
 * CAVLC/CABAC entropy coding
 * Custom quantization matrices
 * Intra: all macroblock types (16x16, 8x8, 4x4, and PCM with all predictions)
 * Inter P: all partitions (from 16x16 down to 4x4)
 * Inter B: partitions from 16x16 down to 8x8 (including skip/direct)
 * Interlacing (MBAFF)
 * Multiple reference frames
 * Ratecontrol: constant quantizer, constant quality, single or multipass ABR,
   optional VBV
 * Scenecut detection
 * Spatial and temporal direct mode in B-frames, adaptive mode selection
 * Parallel encoding on multiple CPUs
 * Predictive lossless mode
 * Psy optimizations for detail retention (adaptive quantization, psy-RD,
   psy-trellis)
 * Zones for arbitrarily adjusting bitrate distribution
